%1.
a = 5+16i
angle(a)
%2.
A = [1 2 3 3;
    2 3 5 7;
    1 3 5 7;
    3 2 3 9]                                % zeros(4,1) 生成插入的矩阵
A = [A,zeros(4,1)]

%3

D = [1+4i 4 3 6 7;
    2 3 3 5 5;
    2 6+7i 5 3 4;
    1 8 9 5 4]

%4
logspace(-3,1,5)                %生成一个5个元素的行向量,第一位为10^-3,最后一位为10^1,公比为10；



%5
z = [1 2;3 4];
zz = [z fliplr(z);flipud(z) flipud(fliplr(z))]%fliplr是沿Y轴镜像，flipud是沿X轴镜像

 

%6
b = [1 2 3 3;
    2 3 5 7;
    1 3 5 7;
    3 2 3 9]
c = b([3,4],[2,3,4])            %取A的3,4 行，2,3,4列

b(:,2) = [];
b(2,:) = []
